October 2007 NVAC Meeting Minutes
Mr. Singleton described the data sources for population-based estimates for vaccination coverage among adults. One of the main sources of vaccination coverage information is the National Health Interview Survey (NHIS), which is an annual in-home survey of the noninstitutionalized population in the United States. Data from the NHIS provide national vaccination coverage estimates on an annual basis. The NHIS is the official monitoring system for the Healthy People 2010 objectives.
Another source of vaccination coverage information is the National Immunization Survey-Adult (NIS-Adult). This is a periodic national telephone survey that was conducted in 2003, 2004, and 2007. The NIS-Adult provides more timely and detailed information about vaccinations than the other systems. A third source of vaccination coverage information was the BRFSS, which provides State-based estimates on vaccination coverage by way of a random-digit telephone survey.
Mr. Singleton compared the three adult vaccination surveys. In terms of schedule, the NHIS and the Behavioral Risk Factor Surveillance System (BRFSS) are annual surveys while the NIS-Adult is a periodic survey done on an as-needed basis when funds are available. In terms of method, the NIS-Adult and the BRFSS are conducted over the phone while the NHIS is a face-to-face survey. In terms of sample, the NHIS and the NIS-Adult are conducted at the national level while the BRFSS is conducted at the State level only.
The advantages of the NHIS are that it is a wealth of other health and access data, it is conducted face to face (and therefore, response rates are higher), and it includes non-landline households. The advantages of the NIS-Adult are that more detailed information is obtained on knowledge and attitudes about vaccination and it is a more flexible and timely survey. The advantages of the BRFSS are that it provides State-based information and that it is less expensive to conduct.
Other immunization surveys are being conducted in U.S. affiliated jurisdictions. These are face-to-face household surveys; for children, shot and medical records are reviewed to verify immunization status. These surveys will be repeated in each of the eight areas every other year.
For the institutionalized population, the National Nursing Home Survey is used. It is a facility-based sampling frame, in which a knowledgeable staff person records the immunization status of a sample of residents. CMS also has the Minimum Data Set (MDS), which provides data on nursing home residents.
Mr. Singleton also mentioned data sources for the Medicare population, which include the Medicare Current Beneficiary Survey (MCBS), Medicare Enrollment and Claims Data, and the Health and Retirement Study. Data sources for pregnant women include the Pregnancy Risk Assessment Monitoring System, which includes questions on the influenza vaccine. One final data source is the National Health and Nutrition Examination Survey (NHANES). For this survey, blood is drawn to determine serologic evidence of immunity for various vaccine-preventable diseases.
Mr. Singleton presented estimates of vaccination coverage by vaccine (tetanus, HPV, MMR, varicella, influenza, pneumococcal, hepatitis A and B, meningococcal, and herpes zoster) among adults. He noted that even though influenza and pneumococcal vaccination coverage levels are below the 2010 Healthy People Objectives, they have been gradually increasing over the years.
Mr. Singleton then discussed gaps in adult vaccination coverage assessments. For example, there is a potential bias with telephone surveys in that they miss wireless-only households. Also, telephone surveys tend to have a higher number of nonresponders than in-person surveys. There are also certain vaccines and target groups missed by the NHIS.